Refrigerating apparatus



VMay 31, 1938. H. F. sMm-l 2,119,494

REFRIGERATING APPARATUS Filed Sept. 30. 1936 I5 Sheets-Sheet 3 256 E 1 H250 252 .1r/4; 5/.2 Y 25 320 52A 238 y INVEIWFOR.

@ya Z g Z ATTORNEYS Patented May-3,1, 1938 y UNri-ED Es FFicE REFRIGERATING APPARATUS poration of Delaware Application September 3i, 1936, Serial No. 103,298

16 Claims.

This invention relates to refrigerating apparatus and more particularly to means for cooling absorption refrigerating apparatus.

Absorption refrigerating apparatus isbuilt in a number of diierent types. It is built in the continuous type in which there is a separate generator, condenser, an evaporator and an absorber. It is also built in the intermittent type wherein there is a combined generator-absorber, an evaporator and a condenser. In the intermittent type, the generator-absorber is alternately heated and cooled, while in the continuous type, the generator is continuously heated, while the absorber is continuously cooled. For the most part, absorption systems have been cooled by water, but in recent years, some systems have been cooled by air.

Ordinarily, when :cooled rby air, this hasbeenv in theqformof natural draft circulation. However, because of the low specific heat of air, rather large amounts of air must be circulated and a large surface must be provided so that in cooling by natural draft. the apparatus becomes rather bulky and heavy. The use of a forced draft clearly reduces the size, weight and cost of the condenser and sometimes the absorber. It is considered undesirable to use an electric motor for circulating cooling air over the condenser because this requires an additional source of power.'

so whereas absorption refrigerating systems are ordinarily operated upon gas or kerosene. Y

It is an object of my invention to provide an absorption refrigerating `system with a cooling means energized by heat derived from the system.

It is a more specific object of myinvention to provide fan means driven by a heat engine which is energized by' heat from the heating means of Athe apparatus for circulating cooling air over the condenser and absorbing means of the absorption refrigerating apparatus. l

, Further objects and advantages of the presen invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings: f

Fig. 1 is-a diagrammatic illustration of a continuous type of yabsorption refrigerating system embodying one form of my invention;

Fig. 2 is a diagrammatic illustration of a simple form of intermittent absorption refrigerating sys-4 tem embodying a modified form of my invention; and

Fig. 3 is a diagrammatic illustration of a multiple 'absorption refrigerating system embodying another form of my invention.

Brieiiy, in the modication shown in Fig. l, I have shown diagrammatically an absorption refrigerating system of the continuous partial pressure y type, sometimes known as the Platen- Munters type of absorption refrigerating system. This absorption refrigerating system is provided with al continuous heater for the generator. Connected to this heater, I provide a heat engine 10 of the Stirling type which drives a fan for circulating cooling air over the absorber and the condenser of this absorption refrigerating system.

In the modification shown in Fig. 2, I have shown diagrammatically an intermittent absorp- 15 tion refrigerating system including a generatorabsorber, an air cooled condenser and an evaporator. In this system, there is provided a pilot light and a main burner which is lighted fromI the pilot light through a flash tube. The main burner operatesintermittently, but the pilot light operates continuously. This pilot light, I also use to operate a Stirling type of heat engine which drives a fan for circulating air over the condenser of this intermittent absorption refrigerating system during the generating cycle and over the generator-absorber during the absorption cycle.

In` the modification shown in Fig. 3, I have shown diagrammatically a twin generator-absorber, condenser, evaporator absorption system. In this system, the one generator-absorber is heated while the other cools. .Each of the burners is provided with a flash tube extending to a common pilot light which also operates a heat engine of the Stirling type which drives a fan for circulating cooling air over the generatorabsorber to be cooled andthe condenser.

Referring now to the drawings, and more particularly to Fig. 1, there is shown an insulated refrigerator cabinet 20, provided with an apparatus compartment 22 at its side. The absorption refrigerating system comprises a generator 2t having a heating iiue 26 extending through its central portion extending from beneath the bottom of the generator to the top of the compartment 22. The upper part of the generator is con- 'nected by a conduit` 28 to the condenser 30 shown in the upper part of the compartment 22 adjacent the outlet 36. The bottom of the condenser is connected to a liquid ammonia receiver 36 which is provided in its upper portion with a bent over hydrogen vent 38. This receiver 36 is connected by a tube 40 which extends through a larger tube 42 to the evaporating means 1. u which isi iocctod within .thc insulated com- ;partment 20. The tubes 40 and 42 serve as a heat exchanger.

The evaporating means 44 is;v provided with aseries ofsuperimposed' stacked pans capable of holding `a thin sheet of liquid refrigerant. The bottom of the evaporator Jis connected by a gas `V tube 46 to an enlarged connecting portion r48 which connects upwardly to the vent 38 and tion by a hydrogen tube 56 which connects with a tube 58 surrounding the smaller tube 50 and serving as a heat exchanger. the hydrogen tube 42 connected to it for conducting hydrogen to the top of the evaporator.

' The lower'part of the generator is connected by a weak liquor tube `which passes through a heat interchanger 62 and thence extends upwardly to the top of the absorber. The bottom of the absorber is connected by a strong liquor tube 64 which passes through and forms the outside of the heat interchanger 62 and vconnects to a vapor lift'pump 66 formed of an ascending spiral tube wrapped around the portion of the flue 26 immediately beneath the generator 24. The upper portion of this spiral vtube-or pump is connected by a conduit or tube 68 to the top of the generator.l

' According to my invention, I providea heating means in the form of a gas burner 18 from which issues a gas name l2 located within the lower portion of the flue 26. This ue is provided with a sort of a boss o'r recess into which extends the head end of. a Stirling type heat engine. 'Ihis heat engine is preferably provided with a displacer, a piston, a connecting rod and a crank shaft and with cylinder portions to be heated and cooled. 'I'he engine may be charged with air either at atmospheric pressure or preferably at some elevated pressure or it may be charged with someother gaseous iluidat atmospheric or a" higher pressure. Preferably, the engine is charged with a gas at a higher pressivne, since this increases the efliciency of the engine.

The engine is continuously heated at its head end by the iiame l2 and is provided with a fan '|6. upon its crank shaft which draws air into the inlet opening '18m the chamber 22 and circulates air through the chamber particularly over the absorber 54-and over the surfaces of the condenser 30, thence vout the top outlet opening 434. In operation, the heat from the burner 12 heats the rich ammonia liquor in the generator f the inner liquid ammonia tube 48 to the upper lower stacked pans.

portion of the evaporator 44 where it is discharged into the upper stackedpans from -whiclt it spills over in the form of cascades into the An atmosphere of hydrogen is present in the evaporator and the absorber, as well as'the connecting hydrogen and gas passages therebetween.

ThiS tube 58 has In this hydrogen atmosphere, the ammonia evaporates according to its ownpartial pressure aided by the circulation of hydrogen. This circulation of hydrogen is eil'ected by `reason of the evaporation of ammonia within the evaporator which mixes in vapor form with the hydrogen, thus making the atmosphere within the evapo rator heavier and causingv it tofall through the passages, in the stacked pansto the bottom of the evaporator and thence through .the connect- 10 ing gas tubes, 48, 58 and 52` to the bottom oi the absorber 54. v

c Froxnthe bottomy o f the. generator 24, weak liquor is conducted' through the pipe 58 tothe heat interchanger 62 where it is cooled and conll5 ducted'to the top of the absorber. where this weak liquor is discharged into the upper-most of the-stacked pans, from which it falls in the form of a cascade into the lower stacked pans. The

absorber 54 is cooled by the flow of air fromthe 20 heatl engine driven fan 15 and as a result, absorbs the ammonia vapor from the ammonia laden hydrogen atmosphere which has Abeen v brought into the absorber-from the bottom of the Only the' hydrogen remains and this 25 evaporator. v hydrogen passes upwardly through the stacked p'ans to the top of the-absorber andthence becaus of its relatively light weight, passes through 'the hydrogenpassages- 55, 55' and 42 to the top of `the evaporator;v In so doin'g, this hydrogen'- 30 gas is cooled by the interchange vbetween the tube 50 which carries the ammonia laden atmosphere. This hydrogen also effects a heat interchange vwith the liquid ammonia carrying utube 43.

Should any hydrogen collect in the receiver 35, 35

portion of the stacked pans, there is'provided 40 the volatile liquid Aheating' Yjacket |22. The solid absorbent spaces are connected by a refrigerant tube |24 to an air cooled condenser |25. This? air cooled condenser |25 is connected by a conduit |28 to an interlock control mechanism |38 which 45 in turn is connected by a tube |32 toa twoway .control valve |34. valve |34 controls the iiow of condensed refriger- -ant from the condenser to theevaporator during ,the generating periodv and-during`r that time |50` maintains a sumciently high pressure within the condenser to condense the ammonia therein and during the absorbing period maintains a predetermined evaporating pressure and tempera` ture withinv the evaporator so as to prevent the 55 evaporator from becoming too cold."` 'I'hls twoway regulating valve |34 is connected by a couduit |36 to an evaporator.|3 8. This evaporator is provided with an insulated receiving chamber.

un which has its bottom portion connected to Al0 the refrigerating surfaces of the evaporator.. The evaporator |38 is located within an insulated food compartment |42 ofa domestic refrigerator. 'I'he remaining portions of the refrigerating system are located lwithin the so-called machine 05 compartment |44 beneath the' food compartment.

' The generator-absorber is heated by a ga's .burner |45.

This gas burner is supplied' with gas through a gas line |48 which connectsto -a pressure regulating valve |58 which controls the 70 pressure of the supply of 'gas through the tube |52 to a gas control valve |54. The control valve |54 controls the supply of gas through the conduit |56 to the gas burner. This gas controlv valve |54 is operated by a pressure responsive This fftwo-way. control.,

bellows |58 which is connected by a tube |60 to the heating jacket |22 of the generator absorber' lows |58, but the opening of the gas valve |54 is prevented by the interlock mechanism |30 which has a lever |62 which engages the lower end of the gas valve lever |68 to prevent the gas .valve from opening until released by the interlock This interlock mechanism |30' mechanism |30. will not release the lever |64 until the refrigerant pressure within the conduit |32 and |28 rises above a predetermined pressure which indicates that the capacity of the generator-absorber is being exceeded and that a new generating cycle should begin. A pilot light |66 and a flash tube |68 are provided for lighting the gas burner |46 when the valve |54 is opened. This pilot light |66 burns continuously and is supplied with gas through a small conduit |10 which is connected to the gas supply conduit |52.

If mere natural draft were relied upon to cool the air cooled condenser |26, the condenser |26 would have to be made an enormous size. In order to avoid this, I have provided a heat engine |18 of the Stirling type which has its head heated by the pilot flame from the pilot |66. This Stirling type heat engine drives a-fan Which draws air through the passages in the condenser and thence through a large duct |80y during the generating period and draws air from around the generator-absorber during the absorption period. The machine compartment |44 is provided with openings |82 for admitting and discharging the circulating air.

In order to enable the fan |80 to draw the air to the surfaces of the condenser during the gen-y erating cycle and to draw the air over the surfaces of the generator-absorberduring lthe absorption cycle, I provide a damper |88 pivoted at |90 which assumes the positions shown during the generating cycle and which assumes an upper dotted line position indicated by the reference character |88' during the absorption cycle. Thus, when the damper is in its lowermost position, the fan |80 will draw the air through the condenser |26. When the damper is in its upper position indicated by the reference character |88', the fan |80 will draw the air over the finned outer surface of the generator to cool the generator.

In order to do this, there is provided a thermostatic bulb |92 between the burner |46 and the bottom of the generator |20 so that this thermostat is directly heated by the burner during the generating cycle. .This thermostat bulb |92 is connected by a tube |94 which connects to a bellows |96 mounted upon thelside of the condenser |26. The movable end of this bellows |96 is connected to a lever |98 which is fastened to and rotatable with the damper |88. This lever ,|98 is connected by an operating rod to another damper 202 which is moved by the lever |98 to uncover an opening 204 in the shroud of the generator during the heating or generating cycle.

Thus, when the burner is lighted, the thermostat is heated, causing its volatile fluid to expand the bellows |96 and move the lever |98, the damper |88 and the damper 202 to the position shown in Fig. 2. When the generating cycle is terminated by the closing of the gas valve |64, the burner |46 is extinguished, the thermostat bulb |92 cools and causes the partial collapse of the bellows |96. This partial collapse of the bellows |96 turns the lever |98, the damper v|86 and the damper 202, all in a counter-clockwise direction so that the damper reaches the position |88 and the damper 202 reaches the position covering the outlet 206v so that air is `drawn by the fan |80 up over the surfaces of the generator to cool the generator-absorber and cause absorption of refrigeranttherein. By using a heat engine, I am able to provide adequate air cooling with relatively small exposed surfaces. `In Fig. `3, I have shown a detailed generatorabsorber refrigerating system. In this system, there is provided a generator-absorber 220 and a second generator-absorber 222 which are connected at opposite ends ofa connecting refrigerant conduit. 'I'hese generator-absorbers may be either of the liquid or solid type, preferably of the solidV absorption type. In this system there is provided a restrictor 224 which divides the refrigerant conduit intotwo parts. On either side of the restrictor, the conduit is provided with an evaporator and between the .evaporator and each of the vgenerators is a condenser. Thus, connected on one side of the restrictor is the evaporator 226, the connecting conduit 238 and the condenser 232 which is connected to the generator-absorber 220. On the other side ofl the restrictor 226 is a refrigerant evaporator 234, a connecting conduit 236 and a condenser 238 connected by a connecting conduit 260 to the gencrater-absorber 222.

One of these generator-absorbers is heated. while the other is cooled so that condensation takes place in the condenser nearest the generator-absorber being heated, While evaporation of refrigerant and refrigeration is provided in the evaporating means nearest the generator-absorber being cooled. When substantially all of thefrefrigerant is driven out of the one generator-absorber, the temperature rises, actuating a thermostat to reverse the process and cause the other generator-absorber to be heated and the one which was heated to be cooled. l

The generator-absorbers and condensers are located in a machine compartment 242 beneaththe insulated food or storagecompartment 244 of a domestic refrigerator. In order to control the circulation of air, I have provided a shroud 246 for the generator 220 and shroud 248 for and the fan duct 250. When the slidable duct 258 is moved to the right in a position `shown in Fig. 3, the shroud of the generato);` 246 is cut 01T from the duct 250, while air may freely be drawn lfrom the shroud 248 into the duct 250. Under such conditions, the generator-absorber 220 is being heated while the generator-absorber 222 is being cooled. When the damper 258 is moved toward the left, ow of air from the shroud 248 to the duct 250 is cut olf and flow is permitted from the shroud 246 to the duct 266. Atvthe same time, this sliding damper 258 Ialso operates the dampers 266 and 262 which open outlets in the shroud 246 and-246 respectively when vtheA shroud is closed by a portion of the sliding damper The control of these dampersis provided by thermostats 264 and 266 which are mounted respectively in heat exchange relation with the :generator-absorber'226 and 222. Y 'I'hese thermo- 1 'stats may be of any suitable type and should be relatively powerful. The thermostat 284 operates --zthrough a set screw 268 upon a lever 216 which is connected by a link 212 to a rotary gas valve 214.

This rotary gas valve is connected on the opposite side by a link 216 to a lever 218l provided-With a set screw 286 whichis adapted to be engaged by the thermostat 266 at the termination of the heating of the generator-absorber` 222;

The rotary gas valve 214 is supplied with gas through a conduit 262 which is provided with a throttling lgas valve 264 which throttles the flow '1 .of gas from the supply gas line 286 to the apparatus. This throttling gas valve 264`is controlled by a thermostat 286 mounted upon the evapo` rating-means and connected by a .connecting tube 266 to the valve 284 in order to control the supply of gas to theburners according to the amount of refrigeration that isA required. The rotary gas valve 214 when in thev position shown inA Fig. 3 is adapted to conduct gas from the conduit -282 'to the conduit 262 which supplies the gas tothe burner 284 for the purpose of heating the gener- I atar-absorber 226. The valve 214 is also adapted to conduct gas fromthe conduit 282 to the conduit 298 which conducts the gas to the burner 268 for heating the generator-absorber 222.

' the gas is supplied to these burners, the burner" In order to light the burners 284 and 298, when 264 is provided with a flashtube, `302, while the burnerl268 isprovided with a ilash tube 864, each of whichv extends to a common pilot light 866 which is supplied with gas through the pilot con- I duit 868 which connects to the supply gas line 286.

Afan 612 through a drive shaft 3I4.

engine is located out of the-path of the sliding The pilot light also serves to lheat the head end of a Stirling type heat engine 3I6 which drivesvthe This heat damper 266 so that it will not interfere with the control of the air ilow by this damper. 258.

The gas valve 2161s provided with a toggle spring 816 which causes the gas valveto assume either one of two positions connected withv either the gas conduit 262 or the gas conduit'296. The v gas valve 214 also operates a lever 3I8 whfic'h is connected to an armor a post 826 which extends` upwardly from the slidable damper 258 so that the damper is moved vin a direction opposite to the movement oi' the gas valve 214. the gas valve214 supplies gas to the burner 284, the damper 266 is in a position` to close-oit the iiow of air from the'generator-absorber 226; while when the gas valve 214 is in a position to supply *.gas to the burner 286, the damperm' will be moved to close oil? the ilow of air from the generator to the fan duct.l

By employing th pilot light to operate .the

heat engine to guide the fan, a very little fuel is required to operate the fan to cool thegenerator and condenser. By the use of the' fan, the

. amount of condensing generator. surface may be materially reduced and by the use of the heat engine, the cost o i' operation of the fan is reduced and no other source of power is required. The heat engine is preferably oi the Stirling type and Thus, when may operate upon the air, either atmospheric pres'sure or higher than atmospheric pressure,` or -it may operate upon other gases. However, other typesof hot air and other types `of heat engines gine energized by heat derived from said heating means for driving said fan.

' 2. An absorption refrigerating system comprising generating, absorbing, condensing and evaporating means, heating means including means `for heating the Agenerating means, means-.for ciculating a cooling'medium into heat exchange relation with said condensing means, and a heat engine energizedxby heatderived from said heating means ior operating said circulating means. 1

v3. An absorption refrigerating system comp rising generating, absorbing, condensing and evaporating .means, heating means including means for heating the-generating means, means for circulating a cooling medium into heat exchange relation with said condensing means, and a Stirling type heat engine energized -by heat derived from said heating means for operating said circulating means. r

4. An absorption refrigerating system comprising generator-absorber means, condensing means and evaporating means, means for heating the generator-absorber means, a pilot light for said heating means,- a fan for circulating a cooling medium intojheatexchange relation with said Acondensing-means,- and a heat engine energized" by said pilot light for operating saidffan.

5i An absorption refrigerating system comprising generator-absorber means, condensing means and evaporatingA means, heating means including means for heating the generator-absorber means, a fan for circulating a cooling medium into heat exchange relation with said condensing means, and a heat engine energized by said heating means for driving said fan.

l 6. An absorption refrigerating system comprising generator-absorber means, condensing means and evaporating means, heating means including means for vheating the generator-absorber means, means for circulating a cooling medium into heat exchange relation with said condensing means,

and a heat'engine energized by said heating means 'for driving said circulating means.

v '1. An absorption refrigerating system comprising generator-absorber means, condensing means and evaporating means, heating means includingf means `for heating the generator-absorber means,

exchange relation with said condensing means.

heating means for drivingsaid circulating means.

8. Absorption refrigerating apparatusincluding a pluralityof generating, absorbing. condensingand evaporating means, heating means including means for alternately heating the generating means, fan means for circulating a cooling medium in heat exchange relation with/saldi@ vand a Stirling type heat engine energized by said v means for circulating a cooling medium into heat .s

condensing means, and a heat engine energized byl a pilot light, and a heat engine energized by said pilot light for driving said fan'.

10. Absorption refrigerating apparatus including a plurality of generating, absorbing, condensing, and evaporating means, heating means including means for alternately heating the generating means, means for circulating a cooling medium in heat exchange relation with said condensing means, and a heatengine energized by said heating means for operating said circulating means.

11. Absorption refrigerating apparatus including a plurality of generating, absorbing, condensing, and evaporating means, heating means including means foralternately heating the generating means, means for circulating a cooling medium in heat exchange relation with said condensing means, and a Stirling type heat engine energized by said heating means for operating said circulating means.

12. An absorptionrefrigerating system comprising generating, absorbing, condensing and evaporating means, a fuel burner for heating the generating means, a` fan for circulating a cooling medium into heat exchange relation with said,v

condensing means, and a heat engine heated by heat derived from the combustion of fuel supplied by the burner for driving the fan.

13. An absorption refrigerating system comprising generating, absorbing,l condensing and evaporating means, a fuel burner for heating the generating means, means for circulating a cooling l medium into heat exchange relation `with said condensingv means, and a heat engine heated lby the combustionof fuel supplied bysaid burner for operating said circulating'means.

14. An absorption refrigerating system comprising a generator and an absorber, means for supplying heat to said generator, and mechanical means for circulating air over said absorber, said last named means being operated by heat derived from said heat supplying means.

15. An absorption refrigerating system comfor circulating air into heat` exchange relation 4 with said absorbing means, and a heat engine energized by heat derived from said heating means for operating said circulating means. 

